Default slide background options are limited to solid or gradient fills, and yes, you can even apply a picture as a slide background. However, picture backgrounds do pose some issues, especially since a busy picture may hamper the visibility of other slide objects such as text or charts. Fortunately, PowerPoint provides options to reduce the intensity of a picture background so that any foreground elements such as text can stand apart.

To learn more, choose your version of PowerPoint. If we do not have a tutorial for your version of PowerPoint, explore the version closest to the one you use.